Scream and Scream Again! (1970)

Description

Major Ken Anders, an officer in British Intelligence, is tasked with protecting a researcher in Malta who is experimenting with a secret weapon. His adversary is Kaspar, who, on Mabuse's orders, is to acquire Professor Larsen's superweapon. Mysterious assassination attempts are made on Larsen. Every time Ken believes he has unmasked his enemy, he is found murdered. A race against time ensues for the weapon, which is located in a laboratory below sea level, leading to a solution in true Dr. Mabuse fashion.